How to choose a fitting?

Pipe fittings are a perfect solution for providing connections for pipelines. Additionally, they can modify pipeline systems by extending the run or altering the pipe flow direction. Various pipe fittings exist for different applications and industries, including water supply, pharmaceuticals, power generation, petrochemicals, pulp & paper, and others. Pipe fittings for water supply come in multiple materials, types, shapes, and sizes. Hawle offers a wide range of mechanical pipe fittings for the most common types of pipes used in the water supply. Prior to selecting the ideal pipe fitting for your application, you should base your decision on certain criteria to assure its compatibility.
Criteria for pipe fittings selection
Choosing the suitable pipe fitting is crucial to ensure the rigidity of the plumbing system. An incorrect pipe fitting can lead to flow restrictions, leakages, and additional costs. Thus, before choosing a pipe fitting, you should consider the following criteria:
- Pipe type
- Pipe diameter
- Material
- Medium
- Shape
- Other parameters like pressure rates, etc.

Selecting fittings based on pipe material
There are different kinds of pipes used in water supply systems, the most common ones are: polyethylene (PE), cross-linked polyethylene (PEX), polyvinyl chloride (PVC), ductile iron, copper, plastic, fiber cement (AC), and galvanized or stainless steel pipes. When choosing a pipe fitting, you must consider the type of pipe and its material. Some of the common pipe fittings we offer at Hawle are discussed below.
Choosing fittings upon pipe diameter
Water supply pipes can be of different diameters, depending on the region, pipe material, and pipeline design. For instance, the main pipe in a water supply system (i.e., water mains) is usually more than DN 400, distribution lines starting from DN 50, and service lines (from the distribution main to the house connection) are commonly less than DN 50.
House connections
Hawle has a broad palette of pipe fittings for house connections up to 2", offering a versatile range of fittings to suit your needs. These include non-threaded pipe fittings, including push-fit fittings,Hawle ZAK connections and and conventional threaded pipe fittings. Pipe push fittings are becoming increasingly popular compared to conventional fittings as they are much faster to install without needing specialized equipment, saving time and money.
Hawle ISO pipe fittings made of ductile iron (with an epoxy powder coating) or polyoxymethylene (POM) are suitable for PE pipes according to EN 12201-2 and DIN 8074, up to PN 16. The Hawle ISO pipe fitting is the ideal push connection for PE pipes that have been tried and tested for decades. The joint is flexible, making the installation of the fitting quick and straightforward. Similar to the Hawle-FIT series, ISO fittings are available in various types: with external and internal thread, connector, elbow 45°- 90°, T-piece, end stop, wall inlet fitting, etc. By using the new 2-K gripring the ISO fittings can be used for PVC pipes acc. to EN ISO 1452-2.
ZAK connections are threadless, restraint-joining systems for service connections. The bayonet-style connection of the ZAK-system is simple and fast, meaning service line connections can be made or removed in seconds. The ZAK-system saves time and does not require separate sealing products to make 100% leak-proof connections. Made from high-quality castings in Europe, ZAK-system fittings are made of GJS-400-15 ductile iron and coated inside and out with a durable epoxy powder coating.
Pipe fittings by material
Ductile iron fittings
Most Hawle pipe connections are made of ductile iron in our foundry EGM Industrieguss GmbH in Austria. They are covered by a layer of epoxy powder coating that is produced using the fluidised bed Epoxy coating technique according to the specifications of the Quality Assurance Association for Heavy-Duty Corrosion Protection (Gütegemeinschaft Schwerer Korrosionsschutz, GSK). Hawle's ductile iron fittings are durable, corrosion-free due to the epoxy coating, and suitable for higher pressures. However, they are relatively heavy compared to plastic fittings.
Fittings by pipe medium
Another crucial aspect to consider before choosing a pipe fitting is the medium inside the pipe, which plays an important role.
Fittings for drinking water
To ensure its safety for distribution, fittings used in the water supply must meet the standards set by European Authorities. These include the drinking water certification, for example, from the Austrian and German Associations for Gas and Water (ÖVGW and DVGW, respectively. Protecting human health and the environment is a top priority at Hawle. Most fittings on the Hawle portfolio are designed for municipal water supply. This means that parts in contact with drinking water are certified and lead-free to ensure their safety for human health and the environment.
Wastewater fittings
Fittings used in wastewater must be robust and withstand more aggressive media (i.e., sewage and wastewater). NBR linings (made from nitrile rubber compound) are used to ensure good abrasion resistance from wet slurry and fine particle sliding. Hawle offers a range of wastewater fittings, which are different types of flanged fittings, System2000 pipe connections and Hawle-FIT fittings, including elbows, reducers, connectors, and T-fittings.
Pipe fittings by shape
Pipelines come in different shapes and sizes. Based on the design of the pipeline, there are various shapes of pipes connectors:
- T-fittings
- Cross fittings
- Duck foot bends
- Elbows of different degrees.
Hawle has a wide variety of fittings and mechanical pipe connections for common pipe types used for water supply or wastewater disposal. Our technicians will advise you if you need any support selecting the suitable fitting for your application.